A spate of bombings in Iraq has given rise in recent weeks to asking how long US troops must remain in the country. Al Qaeda was thought to be all but eliminated from the Sunni Arab provinces and barely holding on to redoubts in the northern Kurdish provinces. But al Qaeda’s recent bombing campaign has caused some to ask if the US will be able withdraw from Iraq by the end of 2011. That’s the wrong question.

Many forces are pressing for the US to remain in Iraq for the foreseeable future. Kurdish and Sunni Arab minorities, fearful of the Shi’a majority, want protectors and may be able to revise the withdrawal timetable established in last year’s Status of Forces Agreement. Israel and Saudi Arabia see eye to eye on few things but fear of Iran (and perhaps an inordinate fear) is one such thing. Both will use their considerable influence in Washington to keep US troops there as a buffer against Shi’a expansion. The US military, having adopted a “see it through” ideology in the wake of Vietnam (distant though that memory now is), also wants to maintain a presence in Iraq until a stable government is established, though no one can say just when that will be.

The question is not should the US leave while Iraq is unstable, it is this: Will Iraq be more stable in three or five years (or more) than it is today? It is unlikely that it will be. Al Qaeda will not be eliminated from Iraq as long as there are US troops in the country. There are enough Salafist groups and enough secular anti-western groups to ensure sufficient indigenous support for al Qaeda fighters. Such people, though not necessarily willing to fight or plant bombs themselves, are willing to provide networks that will help al Qaeda fighters coming in from across the porous borders with Jordan, Saudi Arabia, and Syria.

The presence of US troops in Iraq contributes to al Qaeda’s presence and support there. American soldiers patrolling the streets are a welcome sight in many neighborhoods that saw fierce sectarian fighting over the last four years or so, but many Iraqis and others in the region see them as occupiers and as evidence of American plans to colonize Iraq – and later much of the Middle East.

The Surge helped reduce violence but set up instabilities that are beginning to reveal themselves now. The US helped establish greater security over the last two and a half years by making deals, not with established political groupings but with a miscellany of power holders. Some were young upstarts in tribal structures of the Dulaim and Duri confederations; others were little more than local gang leaders. The deals have caused resentments in the tribes and conflicts are likely to grow as many leaders who had fled to Jordan and Syria are returning to reestablish themselves. Power arrangements are unlikely to be sorted out in the next few years.

The US would do well to leave Iraq according to the withdrawal timetable and reallocate its resources to matters better related to American national security. The US has ousted a dictator and given the people of Iraq a chance for responsible self-government but it cannot build a stable democracy for them. President Obama recently said to US troops in Iraq, “You have given Iraq the opportunity to be a democracy.”

The president’s choice of the word “opportunity” suggests recognition of limits on what the US can achieve there. The implicit acknowledgment of limits to what can be accomplished makes it the most thoughtful statement an American president has made on world affairs since Ike’s farewell address.

Brian M Downing is a political-military analyst, author of The Military Revolution and Political Change and The Paths of Glory: Social Change in America from the Great War to Vietnam, and co-author with Danny Rittman of The Samson Heuristic. He can be reached at brianmdowning@gmail.com.